This invention relates to hydrocarbon getter pumps used to remove hydrocarbons from sealed envelopes and more particularly to a pump employing a catalyst and gettering material.
Sealed single beam oil film light valves used as a part of projection television systems, require removal of hydrogen, methane and heavy hydrocarbons resulting from electron bombardment by an electron beam of a thin oil film located in the tube. The heavy hydrocarbons are removed by a molecular sieve while the presently-used getter pump has a tungsten filament to generate electrons to dissociate the hydrocarbons by electron bombardment, into carbon and hydrogen. The hydrogen is gettered with an active metal alloy of 84% zirconium and 16% aluminum by weight, while the carbon is deposited on the surface of the electron bombardment chamber. The getter material is situated in ring shaped receptacles with the receptacles spaced apart in the axial direction by a wire frame. A tungsten heating element, positioned axially through the ring receptacles, is operated at high voltages to generate heat and electron bombardment. The electron bombardment getter pump has two drawbacks, however. First, the electron emission control electronics required to maintain electron bombardment as the tungsten filament ages is costly, and secondly, the electron emission filament becomes brittle after many hours of operation and may break or burn out if subjected to a small mechanical shock.
It is an object of the present invention to provide a hydrocarbon getter pump that does not use electron bombardment to dissociate hydrocarbons.
It is a further object of the present invention to provide a hydrocarbon getter pump that is mechanical shock resistant.
It is a still further object of the present invention to provide a hydrocarbon getter that does not need control electronics.